This invention relates to a method for the use of a program controlled stirrer for producing pharmaceutical or cosmetic recipes or the like, comprising an electric stirring unit whose revolutions can be controlled, consisting of a stirring unit which reaches into a mixing receptacle, whereby the stirring unit is coupled to a micro-processor which determines the length of stirring time and stirring speed at the stirring unit in a program-controlled manner.
For example, for pharmaceutical or cosmetic medical prescriptions, one step recipes are produced from ointments, powder mixtures, gels and the like. In the singular preparation of such recipes, which usually takes place in pharmacies, the components of the recipe are manually mixed using traditional methods. To do this, mortar and pestle as well as glass plate and spatula can be used. In addition to the risk of contamination to the substances being produced due to the manual procedure, there is also the problem that the conditions in which the mixing of the single substances is carried out are not reproducible and documentable. Thus in the repeated production of the same recipe significant quality differences may result, which could affect the effectiveness of the recipe.
A device for stirring, mixing, chopping or the like is known from DE 196 41 972 C2. Such a device (which can be referred to as stirrer) features a stirring unit and a lifting unit to mix certain substances together using a stirring tool in a mixing container in a partly automatic manner so as to obtain the desired recipe as a result. With this device, according to the state of the art, it is possible to change the stirring speed, the stirring time, the stroke rate and the lifting speed within set limits so as to adjust them to special types of recipes. These parameters of the stirrer must be adjusted to the characteristics of the initial substances as well as to the relevant amount of these substances for the result from the mixing process to be satisfactory. The disadvantage of this known device lies in that the optimal parameters of the different mixing processes do not remain available for a long period of time and therefore must constantly be re-input. Individual inputs of mixing time, number of revolutions per minute of the stirrer, lifting speed and stroke rate are not reproducible at a later point in time. Thus, special recipes, both in the case of their production by different pharmacies and in the repeated production by the same pharmacy at different points in time, can have highly variable qualities. In this way, for the same medical prescription a quality uniformity (Good Manufacturing Practice—GMP) cannot be assured.
DE 39 19 534 A1 shows a method and a piece of equipment for the preparation of bone cement. According to this method, an automatic process command is provided so that the mixing phase and/or the rest phase are selected in consideration of the relevant type of bone cement and the amount of it being used. The operation of the described piece of equipment is, however, relatively costly because the control parameters must be manually input. Moreover, the documentation of the mixtures obtained is not assured and therefore the repeatability for identical mixtures cannot be guaranteed.
A method for the control of stirring processes is known from DE 31 26 552 A1. Based on the viscosity of a substance, the optimum power input of the stirrer is adjusted. Additionally, the viscosity can be continuously set during the stirring process. Repeatable, documentable and fast production of mixtures from the automatic use of the parameters based on container size is therefore not achieved.
Finally, DE 43 02 085 C1 reports on a method for the dosing and mixing of dental filling substances made up of several components and on the piece of equipment for the application of the method.
One task of this invention is to minimize quality differences in the production of individual ointment recipes. An additional task lies in facilitating the use of stirrers so that cosmetic and pharmaceutical products can be produced with the desired quality even by less qualified personnel. Moreover, the invention must allow for the production of individual recipes resulting in equal quality that are produced with long time intervals between productions and enable an increase in effectiveness in the repeated production of such recipes.
These and other problems are solved by a method which includes the following steps:                Input of variable data into data input devices which define at least:                    the amount and the category of the recipe to be produced within a given tolerance range and,            the size of the mixing receptacle;                        Input of nonvariable data from a data memory which, for preset categories of recipes and sizes of mixing receptacles, contains the basic values for the stirring time and stirring speed;        Determination of the length of stirring time and stirring speed in order to produce the desired amount of the recipe by combining the variable and nonvariable data;        Conversion of the determined length of stirring time and stirring speed into corresponding initial current or voltage values and control of the stirring unit with these control parameters;        Storage of the control parameters adopted during the production of the recipe, together with identification data in a data memory;        Output of the control parameters and/or identification data adopted, through a data output device, in electronic and/or printed form.        
The main advantage of the stirrer according to the invention lies in that a GMP-compliant quality uniformity of the recipes to be produced can widely be assured. It is guaranteed that the same recipe will be produced using the same mixing conditions. Moreover, errors in the use of the stirrer are widely prevented.
An advantageous embodiment of the program controlled stirrer also includes a lifting unit, through which the relative position of the stirring tool in the mixing receptacle can be changed during the stirring process, whereby the data-processing program executed by the micro-processor includes the following steps:                Determination of the necessary stroke rate and lifting speed in order to produce the desired quality of the recipe by combining the variable and nonvariable data;        Conversion of the determined stroke rate and lifting speed into corresponding initial current or voltage values;        Control of the lifting unit with said initial current or voltage values.        
The inclusion of the lifting unit in the control through the micro-processor further increases the quality uniformity required by the Medicines Act. Moreover, in this way it is also possible to adjust the stirring mode to the special initial substances and the desired end product. At this point it must be specified that in this context the word “stirring” also refers to the chopping of the initial substances, the mixing and blending of the initial substances as well as any other kind of preparation that can be performed by the stirring tool in the mixing receptacle.
By using the program controlled stirrer, ointments, gels and other pasty masses can be produced. Besides, single powdery substances can be blended together if this is necessary for a certain recipe. Different stirring tools can be fitted, which in size and shape are adjusted to both the mixing receptacle and the mixing task to be fulfilled.
According to a practical embodiment, variable data on the viscosity of the initial substances is input through the data input devices. If required, additional data describing the substances or guideline values concerning the stirring time, the stirring speed, the stroke rate and the lifting speed can also be input. When using guideline values, the program controlled stirrer compares these guideline values with the minimum values stored in the data memory and adopts these minimum values if the guideline values are below the minimum values. In this way a seriously incorrect condition of the stirrer is avoided because a minim quality of the relevant recipe is guaranteed by the application of the minimum values. In another modified embodiment it is also possible to compare the guideline values with maximal values stored in the data memory.
A particularly preferred embodiment of the stirrer enables the storage of the control parameters adopted during the production of the recipe, i.e. either the stirring time, the stirring speed, the stroke rate and the lifting speed or the current or voltage values being utilized to command the stirring unit and/or the lifting unit. This data is combined with the individualizing data so that, at a later point in time, the special control parameters adopted can be tracked back through the individualizing data, should an identical recipe be produced again. As another advantage, this measure also brings about a significant time saving because the control parameters for the stirrer must be input only once and can be quickly called up from the data memory for a later production of the same type of recipe.
In another enhanced embodiment of the program controlled stirrer, an output unit is also provided, through which the control parameters to be adopted and, if required, also the identification data, can be output. For example, the identification data can be printed on a label that can be put on the packaging of the produced recipe. In this way, the identification data is available when a new order of the same recipe is made with the used packaging unit.
Obviously the output of the data in electronic form is also possible. In other embodiments, the data can be coded in a bar code so that all of the control parameters can be input with a scanner. This would also allow for standardization of the production in different pharmacies, seeing that not only the identification data but also the entire control data set can be encoded in a bar code.
When the program controlled stirrer is assembled as a stand alone device, a keyboard, a touch screen or a similar data input device is provided in order to store the variable data. In a modified embodiment, a PC is fitted with a data connection available for data input and also for data storage. The data connection, for example, can be made through a serial interface. This is particularly advantageous because in this way traditional computers can be used which are equipped with a special control program.